Posted
by
samzenpuson Wednesday February 03, 2010 @10:28PM
from the part-time-collision dept.

quaith writes "ScienceInsider reports that Europe's Large Hadron Collider will run at half its maximum energy through 2011 and likely not at all in 2012. The previous plan was to ramp it up to 70% of maximum energy this year. Under the new plan, the LHC will run at 7 trillion electron-volts through 2011. The LHC would then shut down for a year so workers could replace all of its 10,000 interconnects with redesigned ones allowing the LHC to run at its full 14 TeV capacity in 2013. The change raises hopes at the LHC's lower-energy rival, the Tevatron Collider at Fermi National Accelerator Laboratory in Batavia, Illinois, of being extended through 2012 instead of being shut down next year. Fermilab researchers are hoping that their machine might collect enough data to beat the LHC to the discovery of the Higgs boson, a particle key to how physicists explain the origin of mass."

We saw this coming in 2028, and needed to have them shut this down so that they'd lose a year. This alters the timeline sufficiently. If all goes well, no other adjustments will need to be backdated until 2013. Where's Shroedinger's cat, by the way?

at (apparently) no one being fired for designing interconnects that only allow the LHC to run at 1/2 power? I may not be a scientist, but shouldn't a design cover the requirements? Then, to lose a year's work on top of that, and no one is getting their wrist slapped or even sued?

Looks like a perfectly reasonable NP to me ([[government woks] projects]), so although you may have pragmatic problems it's no grammatical abomination. Your missing apostrophes in the follow-up post, turning two VPs into genitive pronouns, are the real grammatical issue (and even then don't obscure understanding).

The interconnects are rather complex superconducting devices, not simple electronic connections. It certainly would have been possible to design them with a higher safety factor, but that would have increased the cost. If that approach had been taken with all of the critical components for the machine, the overall cost would have been significantly higher. Unfortunately for a large cutting edge project on a tight budget, you need to take some technical risks. Over the next 10 years we will see if they put a reasonable safety factor on the overall design.

It certainly would have been possible to design them with a higher safety factor, but that would have increased the cost...Unfortunately for a large cutting edge project on a tight budget, you need to take some technical risks.

Governments work on a steady flow of funding. There is no way to deliver one thing in year one with ten years budget without making the guy who authorized it lose his job. Better to cut costs and use future budgets to fix the problem.

Pay no attention to the man behind the curtain. Or in this case the central banks who print money for the government all the time so that they can spend more than their budget would allow. And borrowing. Let's not forget that.

Sure, for a certain project you might not be able to overspend, but as a whole let's not pretend government budgets are fiscally responsible in any way.

I seem to have heard this argument before.
The Apollo fire. The loss of the Challenger. Repairs to the Hubble.

I seem to have heard this misconception before. The Apollo fire wasn't because of a cutting-edge project taking technical risks, or making a considered judgement to accept smaller safety margins in exchange for reduced costs.

Having a mixed-gas oxygen-nitrogen atmosphere in the Apollo capsule would have increased the internal capsule pressure in orbit, requiring a beefier structure and more weight. More dangerously, it would have required the development of suitable partial-pressure sensors for the precise measurement of oxygen levels within a mixed-gas environment. That would have constituted a technical risk. In contrast, the system used in the original Apollo design required only a simple pressure gauge to ensure sufficient oxygen for the crew.

Moreover, in orbit the Apollo capsule internal pressure would be only about 5 psi - about a third of an atmosphere. While that pressure of oxygen is sufficient to support combustion, it isn't dangerously high, and all of the materials used aboard Apollo were tested for fire safety under those conditions. The big problem was that on the launch pad, the capsule contained a full atmosphere of oxygen (the excess pressure would be bled off as the capsule ascended to orbit). Nobody thought to test under those conditions. Even then, there's at least some evidence to suggest that it was the astronauts' webbing the capsule with large amounts of Velcro that allowed the fire to spread so rapidly.

Finally, the earliest design for the Apollo capsule hatch opened outwards and was equipped with explosive bolts for rapid egress. It was at the insistence of astronaut Gus Grissom (who may have been the victim of premature triggering of such a system on his Mercury capsule) that the hatch be replaced with an inward-opening, 'plug' design that lacked explosive bolts.

Both previous manned U.S. space capsules (Mercury and Gemini) had used essentially identical pure oxygen atmospheres, without concern and without any problems. Did they get lucky? Absolutely, in retrospect. Should the Apollo engineers have recognized the dangers that their predecessors had overlooked? Probably. Was the fire the result of taking 'technical risks' on a 'cutting edge project'? Nope. They thought they were sticking with a simple system that had worked for years, and didn't want to asphyxiate an astronaut by fiddling with something reliable.

Noted historian Wikipedia mentions a number of worries in the original design [wikipedia.org]. You are definitely correct about the oxygen, weight, etc. However, uninsulated wire and flammable materials were brought up by the astronauts before delivery. If only they'd been adequately listened to...

Compromise is critical part of engineering - one of the reasons that "no compromise engineering" adverts are so silly. You can always make something better if you are willing to spend more money. You can improve one parameter if you are willing to give up on another. For example airliners are designed with something like a 1.5X safety factor on strength (above maximum loads). If the safety factor was 2X, probably a couple of in-flight break-ups would have been avoided, but the overall cost of air travel wou

I seem to have heard this argument before.
The Apollo fire. The loss of the Challenger. Repairs to the Hubble.

The difference here is that they know what the current safe maximum is, so they'll operate it for a while, tear the thing down and replace them with interconnects with higher safe maximums, and start it up again. They are aware that the lower safety factor must also mean a lower-power experiement (not that putting 7 TeV of energy into a single proton is normally considered low power).

The thing is, the greatest discoveries very often come at a great risk. The risk-averse culture than has steadily been introduced since, say, the 1970s probably greatly holds back mankinds progress. No longer are victims of cutting-edge technologic failures hero's, instead their designers are the victim of outrage and lawsuits. This makes me very sad. Risks are not something bad, risks are things taken by brave people. Very often those people are the ones responsible for great leaps in mankinds progress.

Therefore the argument you quote is not just a good argument, it is a great argument. Wimps that cannot handle it should stay away from it and keep their mouth shut.

There was nothing wrong with repairs to the Hubble. If they skimped and scraped, it has yet to bite them in the ass. The repairs to the Hubble are the most outstanding bit of spaceflight humans have done since leaving the moon. Each mission was a success - extending the life of the telescope and giving it greater and greater capabilities. It was always meant to be so.

If you are referring to the original flaw in the Hubble mirror, I think you'll find it not so clear cut, either.

Well if you want to explore new physics, almost by definition you can't be absolutely sure of what will happen. Present theories do not predict that the LHC can produce a macroscopic black hole, but of course can't rule it out with 100% certainty. The only way to be absolutely certain is to not do anything new. Its similar to deciding not to produce a faster network switch because the internet might become a vengeful hyper-intelligent AI and kill us all. You can't prove it won't happen.

Frankly, I'm a little sick of the "outrage" every time something doesn't go as planned. Since when does the universe have to play nice all the time?

Science, by its very nature, deals with the unknown. We're at the point now where it looks like we're going to have to assemble thousands of experts, using billions of dollars to continue to make fundamental discoveries. If any of us had a road map, I assure you that we'd use it. This means that sometimes, we spend all that time and energy and hit a dead end.

But here's the cool part: dead ends are sometimes better than confirming what we already knew. There was an interview with a theoretical physicist on the radio the other day, and the interviewer asked him what his worst fear and greatest hope for the LHC was. He said, "They're the same thing. We find out that we were completely wrong about something." This is simultaneously frightening and exhilarating, and it's what makes fundamental research so exciting.

Only fundamental research into particle physics. There are plenty of equally fundamental research areas (genetics if you are practically-minded, math if you're not) which don't require billion dollar budgets.

Personally, I see the whole "physics is the ultimate science" as a con to graft in more grad students.

Personally, I see the whole "physics is the ultimate science" as a con to graft in more grad students.

The world is not a nasty, nasty, vile thing that's out to get you. Take a deep breath. Sometimes, really, people mean what they say. Sometimes they act in earnest. Sometimes there is no ulterior motive.

You remind me of the kid at school who would ask what relevance every single thing they were being taught would have in a work place.

I think it reasonable to expect taxpayers to get something back from it

You mean like the computer you wrote your post on? The medicine that has roughly doubled life expectancy in the developed world in the past few hundred years or so? What you seem to be advocating is akin to the recent UK government plans to assess potential economic benefits of research before granting funding which has met with considerable opposition [independent.co.uk]. Private enterprise is c

"You remind me of the kid at school who would ask what relevance every single thing they were being taught would have in a work place."

If you're going to be patronising you might try and get the point first.

"You mean like the computer you wrote your post on?"

Funny you should mention that - Babbage was given government money specifically to build a machine to calculate log tables amongst other things that could be used by the navy. When he failed to produce funding was withdrawn. Electronic computers came ab

OMG..The real truth is out there. This is just an excuse to have the device shut down during 2012. They didn't want to be responsible for the 2012 Mayan prophecy coming true. It make so much sense now!

Not that I believe that sort of thing but it is the first thought that popped in my head while reading the summary.

If you are from then US you are paying for it. The US has provided the LHC with a substantial mount of funding.

Having said that, its a >20km super fluid helium (about 1.4K IIRC) superconducting collider with voltage and magnetic fields at the very limit of what we are capable of. The miss management part of the project was miss managing expectations. There is no way we should expect this to run as a typical engineering project with only one or two delays and cost over runs (typical in most large engineering projects).

To give you an idea of just how far from typical engineering this is, take super fluid helium as an example. It can leak fast out of holes not much bigger than an atom. Also in the super fluid phase the thermal conductivity is insane, but one little spot thats just hot enough to get a small area just above the critical temperature (~2K) then... that area is effective thermal insulator compared to the super fluid and then you can't keep your magnets cold cus you cant get rid of parasitic thermal loads quick enough. Now lets make a connector for this stuff, and put a 10kA cable inside... We need 10 000 of em.

We choose to do these things not because they are easy, but because they are hard.

Just to add some perspective on the US cost, note that the US contribution is about $500 million [newsweek.com] - also remember the LHC has been constructed over about a 15 year period I believe, so on average that's a yearly cost of $33 million. For comparison, the US yearly military budget is over half a trillion dollars.

Alternatively, based on estimates of the cost of the Iraq War [wikipedia.org], of $2-3 billion a week, the entire worldwide cost of the LHC over 15 years is about 3-4 weeks in Iraq...

The Big Deal about the LHC isn't just the energy. It's also that it allows for a much higher collision rate than the Tevatron. Even if you only run the thing at Tevatron energies, it's possible that it can collect as much data in a week as the Tevatron could in years.

When the LHC guys down the hall show up tomorrow I'll have to ask them about the planned luminosity in the first year of running.

Cross sections for most interesting processes go up with a large power of E (~6) at a hadron collider. This is largely due to the gluon parton distribution functions: as you go to higher proton energies, you need smaller and smaller fractions of the proton energy for heavy particle production, and at small fractions of the proton energy, there are gillions of gluons. This has the additional interesting effect that heavy particles are primarily produced at rest, because the less of the proton's energy you

Pardon me for my ignorance. What I don't understand is: do none of these problems show up when a short segment of the ring is built and operated at somewhat above its target power? I get the impression that the failures are in magnetic focusing components rather than the beam. Is that not correct?

The failures, or rather misdesigns/misbuilds, are in "copper bus bars". These effectively act as shorts across the superconducting electromagnet coils. Since the coils are normally superconducting (when at cryogenic temperatures), the short does nothing. But if the coil gets ever so slightly above its critical temperature, it ceases to be superconducting. At that point, it still has very very low resistance, but the current through it is so enormous that it heats up rapidly. When it gets to a certain temperature, its resistance becomes comparable to the resistance of the copper bus bar shorting it, and the current starts to flow more and more through the copper, thus protecting the superconductor from getting too much hotter. At least, that's what is supposed to happen.

What is wrong is that some of the solder joints for the bus bars are not good, and have too high of a resistance. A higher resistance in the bus bar system means a higher superconductor temperature before the current starts to flow through the copper, and in the end, this means damage to magnets.

I'm not sure what level of testing was done, but building a short segment and testing it up to slightly above design spec is probably not really feasible. In order to get the particles to the eventual energies, you need the whole ring to be in working order, because it takes tons of complete circles around the ring to accelerate the particles. Injection from the SPS to the LHC occurs at 1/14th the design beam energy, and the LHC ring takes it up from there.

Even if you could inject 7 TeV protons into a short segment of the ring, you'd still not be able to get the design beam intensity that way, because you don't have all 2000+ bunches ready for injection at once.

You could run the magnet intensities up to what is needed to bend a beam in a tight enough circle at high enough energies even without any actual beam in there, and this was probably done. However, quenches (magnets getting above critical temp) happen principally because of the beam. The beam loses particles and energy at a fairly high rate due to a variety of effects, and all those particles and all that energy goes into heating something, usually the bending magnets. I suppose you could do a deliberate quench by playing with the cryo, though. Perhaps that was done, and we were unfortunate enough to have tested only good subsystems this way.

As you may have guessed, I am a particle physicist (on CDF), but not a beams engineer. So, some of the above is guesswork, but I hope I've been able to relieve some of your ignorance.

Yes - that is a very serious problem. Superconducting magnet systems are designed to shunt the quench energy through some sort of dissipating resistor, but it is a very tricky business. Basically you switch a resistor in series with the SC coil. Sound easy until you think about 10,000 Amps and megajoules of stored energy.

Fellow Slashdotters, I hope is becoming abundantly clear by now that an age is ending; the great 20th century scientific projects are fading into history, and the 21st century will require us to dramatically lower our expectations for scientific civilization. What exactly is the payoff for the LHC anyway? In what way does it inspire society at large or contribute anything useful? It’s very strange to be living through the collapse of your own civilization, but with each passing day it becomes more

In a way the LHC may be the last project of the grand old empire. It may be scaled down from the SSC, but it is still by many measures the largest and most complex machine ever created - designed to understand the most basic physics. 30 years ago you wouldn't have needed to ask what it was for, any more than you would have wondered why were were spending money to go to the moon, or to send spacecraft to Jupiter and Saturn.

With the end of the cold war we no longer feel the need to prove our superiority by bu

I very much doubt that the LHC will find the Higgs in its 2011, 7TeV
is plenty of power to find a Higgs between 100 and 200 GeV, however
the luminosity of the LHC and the number of collisions it will make
is a lot lower too. The LHC will only deliver about 1 inverse femtobarns
in that time. But the Tevatron has will a built up to 8.5 inverse femtobarns
of collisions in that time. That means that the first years run of the LHC
will be a drop in the ocean of the already existing Higgs data from the
Tevatron. So hard luck Europe, but the LHC won't detect a Higgs before
2013. The Tevatron might just see the beginnings of a signal, but probably
not enough to confirm anything.

That blurb genuinely does annoy me - it's almost like it's being made out to be a Europe vs USA thing. It's not - the labs do different experiments for the most part, and it's pretty sad to see science turned into a "who gets there first" style gameshow. Makes me sad:(

I used to work on the software handling the test results from hardware commissioning of the LHC, and an inevitable conclusion is that a lot of smart people did a lot of work to get the accelerator working as well as it does, given the restrictions and unknowns of the project.

The beam energy at 7TeV is 362 megajoules. This is about the energy that you could get by maxing out a household mains connection (230V 20A) for one day, or about the energy content of 11 liters of gasoline. Quite a bit, but not huge at energy scales.

Of course, the beauty of the LHC is that it accomplishes this energy in the form of a particle beam circling the collider at near the speed of light. This means that the power of the beam is about 4 terawatts if my math is right, so it could power about 3300 DeLorean time machines (not for very long, though). Keep in mind that this power is circling endlessly in the LHC, so it isn't being consumed - the actual electric power consumption to run the whole LHC is "only" about 120 megawatts.

Yup, synchrotron radiation. This is significant with electron accelerators, but the LHC accelerates heavy ions where it isn't that much of a problem. The synchrotron power emitted is about 3.7kW in total.

Most mythologies? Can you list them? I thought that only some mythologies even included an end-of-the-world scenario, and of those, almost all are wise enough not to give a date. So I'm puzzled by this claim. Can you specify which mythologies include an end of the world in 2012, so that we can see whether they form a majority?

... for sciences that are of more immediate benefit. I have nothing against blue sky research in particle physics but in general its a fairly esoteric area of research that produces little of value that trickles back to mankind as a whole. I'm really not convinced this level of funding should be spent on it when other areas of science and technology struggle to get ANY sort of funding. I believe that research budgets should be based on the potential value of any results that may crop up and nice it may well

BTW, engines aren't going to get much more fuel efficient. The area to improve now is to reduce vehicle weight and size, which is an uphill battle against safety requirements (SUVs really upped the ante in the safety arms race in the late 90s/early 2000s), cost (the cheapest ways to improve safety are to add steel and increase size...oh wait), and image-related issues such as "big is safe, think of the children!" and "I want a big car because I'm insecure about my penis size."

If the LHC was designed properly, run the friggin' thing. If not, fix the friggin' thing.

Did you RTFA? That's exactly what they're doing. It takes time to come up with a proper fix, but while you're coming up with something, why not use the thing? Even at a fraction of its energy, the LHC is the most advanced accelerator in the world. It would be a shame to just let it sit there.

If the LHC was designed properly, run the friggin' thing. If not, fix the friggin' thing.

Did you RTFA? That's exactly what they're doing. It takes time to come up with a proper fix, but while you're coming up with something, why not use the thing? Even at a fraction of its energy, the LHC is the most advanced accelerator in the world. It would be a shame to just let it sit there.

Without even counting that running it will stress some other hardware and uncover some other potential problems.

Hard to get all worked up about this when the people running the program don't seem to be concerned about accomplishing anything significant. Sort of like spending untold billions on a supersonic aircraft, and after all the money is spent, flying it subsonic for a year or so, and then grounding it for another year to re-wire it.

Well, no. It sounds like they're quite concerned about doing something useful after spending those billions of euros. They still have the most powerful particle accelerator on Earth by a good margin, even if it's not up to its full design power (yet). They can do some solid science, good experiments, collect a year's worth of data and test all of their detectors and other hardware.

After that, they'll have a year with the beam turned off, in which they can actually analyze the mountains of data that we

Because the two machines operate at different collision energies. The Higgs cross section is going to be different at each collider due to this energy difference, so when you go to measure this cross section you're going to get different results.

You can perform a meta-analysis, whereby you make a "best measurement" at different colliders and energies in order to better understand the measurements. However, that's not what you're proposing; you're proposing that they combine data in order to get a result i